This invention relates generally to the harvesting of maple tree sap used in the production of maple syrup and, in particular, to a tree-insertable tap that can be easily and securely closed when the tap is not in use or during periods when the lines used to bring the sap to a production shed are being cleaned.
In the commercial harvesting of maple sap used in the production of syrup, it is not uncommon for the producer to have tens of thousands of taps working at any one time. Where the terrain permits, the main and branch lines leading to the production shed are arranged to transport the harvested sap to the shed under the influence of gravity. Otherwise, where the land is flat, pumps must be used. Each of the taps is connected into the main or branch lines by means of a relatively short drop line.
Maple sap will become rancid if it is allowed to stagnate in any one place for a relatively short period of time. Care, therefore, is taken, even when the sap is running, to avoid low regions in the lines where the sap might stagnate and eventually spoil. Rancid sap contained in the lines can contaminate running sap passing through the effected regions and thus degrade or even spoil an entire production run. Similarly, after the sap has been gathered, the lines must be washed out before being placed in storage. Washing is generally accomplished by running a rinse solution through the lines including the drop lines leading to the taps. In northern latitudes, where gnawing rodents are not a problem, the lines are generally left upon the trees all year long. In other areas where rodents are prevalent, the lines are taken down and washed prior to being placed in storage. During the wash process, the taps are removed from the tap holes and the spout holes closed before the rinse solution is introduced into the lines. To insure that each drop line is throughly cleaned, the spout hole of each tap may be opened for a short period of time to permit some of the solution to bleed through the spout. The spout is then quickly closed and the closure device allowed to remain in place until such time as the tap is to be inserted into a tap hole. As can be seen, where tens of thousands of taps are involved, these opening and closing operations can be arduous and time consuming.
Pluggable taps of all types have been known and used in the art for quite some time. These pluggable taps range from devices utilizing simple short insertable stoppers to more complex devices having means for locking the stopper in the spout hole. Short untethered stoppers are extremely difficult to handle, particularly when the workers are wearing gloves, and often times are dropped and lost in foliage or snow. A short stopper sometimes will not provide a very secure closure because of the lack of bearing surface provided between the stopper and the spout and can thus easily fall out of the spout hole. Small insects of all types can then find their way into the lines thereby clogging the lines and rendering them unsuitable for use during the next harvest.
Bulkier threaded-type closures are sometimes used that are connected to the taps by means of a lanyard or the like and are thus readily available when needed. Once the closure is threaded onto the spout, it will provide a relatively good seal for a limited period of time. However, because the mating parts are typically made of plastic, the integrity of the fit is degraded with use and changes in climate and the tap eventually leaks at the threaded joint. The threaded taps are also relatively expensive to manufacture when compared to simpler plug devices and are extremely difficult to manipulate during cold weather consuming a good deal of the operator's time particularly where thousands of taps are involved.